The present disclosure relates to a multilayer ceramic capacitor and a board having the same mounted thereon.
A multilayer ceramic capacitor, which is one of multilayer chip electronic components, is a chip shaped condenser mounted on printed circuit boards of various electronic products such as a display device, for example, a liquid crystal display (LCD), a plasma display panel (PDP), or the like, a computer, a smart phone, a mobile phone, and the like, to serve to charge electricity or discharge electricity.
Since this multilayer ceramic capacitor (MLCC) has advantages such as a small size, high capacitance, easiness of mounting, or the like, the multilayer ceramic capacitor may be used as a component of various electronic devices.
The multilayer ceramic capacitor may have a structure in which a plurality of dielectric layers and internal electrodes having different polarities are alternately stacked while being interposed between the dielectric layers.
Particularly, in a power supply device for a central processing unit (CPU) of a computer, or the like, voltage noise may be generated due to a rapid change in load current during a process of supplying low voltage.
Therefore, a multilayer ceramic capacitor has been widely used in the power supply device as a decoupling capacitor for suppressing voltage noise described above.
The multilayer ceramic capacitor serving as a decoupling capacitor needs to have low equivalent series inductance (ESL) in accordance with an increase in an operational frequency thereof. In order to decrease this ESL, a great amount of research has been conducted.
Further, in order to more stably supply power, the multilayer ceramic capacitor serving as a decoupling capacitor needs to have controllable equivalent series resistance (ESR) characteristics.
In the case in which an ESR value of the multilayer ceramic capacitor is lower than a required level, an impedance peak generated in a parallel resonant frequency due to the ESL of the capacitor and plane capacitance of a micro processor package may increase, and impedance in a series resonant frequency of the capacitor may excessively decrease.
Therefore, in order to allow a user to implement flat impedance characteristics of a power distribution network, ESR characteristics of multilayer ceramic capacitor serving as a decoupling capacitor needs to be easily controlled.
With regard to the control of the ESR characteristics, a method of using a material having high electrical resistance in external and internal electrodes may be considered. The method of changing a material as described above may provide high ESR characteristics while maintaining a low ESL structure according to the related art.
However, in the case of using the material having high resistance in the external electrode, a localized heat spot causing a current crowding phenomenon may be generated due to pin holes. Further, in the case of using the material having high resistance in the internal electrode, in order to match the material with a ceramic material in accordance with an increase in capacitance, the material used for the internal electrode also needs to be continuously changed.
Therefore, since an existing method for controlling ESR has disadvantages as described above, research into a multilayer ceramic capacitor capable of controlling the ESR has been still required.
In addition, in accordance with the recent trend toward the rapid development of a mobile terminal such as a tablet personal computer (PC), an ultra book, or the like, a micro processor also has been miniaturized and highly integrated.
Therefore, an area of the printed circuit board has decreased, and in a similar manner, a mounting space of the decoupling capacitor has been limited, such that a multilayer ceramic capacitor capable of satisfying the limited mounting space has been still required.